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H. P. JACKSON. ELECTRIC INSULATOR,

APPLICATION FILED MAYH. 1915.

1,303,324. Patented May 13, 1919..

WITNESSES: INVENTOR Pay P. Jae/r550.

- ATITORNEY Y r, ancxsoinon nncnwoon rnnx-rnrmsznvamn, nssrcrronlro mns'rmcnousn nnnornrc AND-MANUFACTURING oomrnnr, oonroanrrononnnniwsxnvnnm nnncmcmsumoa Specification of Letters Patent. Patented May 13, 1919.

Application filed May 14, 1915. 'Seria1No.2 8,053.

and it has special reference to strain insula-.

tors that are adapted to be connected in flexible series. The object of my invention is to provide a strain insulator of the above indicated char-'- acter'which shall be simple in construc'' tion, rugged and durable in operation and elficient' in its electrical characteristics.

The single figure of the accompanying drawing is a side view, partially in elevation and partially in Section, showing two associated strain insulators constructed in accordance with my invention.

As shown, each insulator section consists of a flanged metal cap 1, provided on its concave side with two concentric rings 3 and 4 which together form an annular channel, the

walls of which should be corrugated or otherwise roughened. A hollow cylinder 5,

-, composed of porcelain orother suitable insulatin material, is received within the an nular c annel formed by the rings 3 and A, the inner and outer sides of the walls of the cylinder, which are engaged bylthe corrugations on the rings 3 and 4 being correspondingly corrugated. Layers of cement 6 and 7 are interposed between the porcelain cylinder 6 and'the rings 3 and 4, respectively.

The outer Wall of the porcelain cylinder 5 is" preferably provided with transverse corrugations throughout its length for the' purpose of providing an increased creepage dis- I tance between the metal parts of the insulator. The lower end of'the cylinder 5 isat- V tached to a metal disk 8 which is provided with an internally corrugated annular channel similar to the channel formed in the cap 1 and the lower part of the porcelain cylinin the county of Alle- Pennsylvania, have inattachingmeans comprises a hook 11 formed der is secured in this channel by layers of cement 9 and 10.

Each insulator section is provided, at the top and bottom, with means for attaching the sections to each other and to the usual support. In this particularinstance such on'the top of thepap member 1 anda perforated ear or yoke 12 formed on the bottom of the disk 8. It will be observed that the insulator sections which I have shown and described are extremely'simple and inexpensive in desigib and are, at the same time, more durable than ordinary insulators of the same general type,v

since they have no fragile flanges to broken oil. These insulators have the additional advantage that, when assembled in V series, as shown, the electrostatic stresses imposed on the insulating members are substantially uniformly distributed because of the substantially uniform distribution of the electrostatic field surrounding the porcelain insulating tube by reason of the metallic caps 1 acting as electrostatic shields. The details of the structure which I- have shown and described'may be varied in many particulars without departing from the spirit of my'invention, and 'it is therefore to be understood that no limitations are to be imposed upon my invention except such as are indicated in the appended claims.

I claim as my invention: v

1. A suspension-type insulator comprising metallic end membershaving annular channels provided with uneven walls formed therein and a tubular insulating member for s5 being provided with both exterior zmd interior grooves and received in said channels of said end' members and one of said metallic end members having'a laterally extending outer flange formed thereon to effect a sub- 1 stantially uniform distribution of the electrostatic field surrounding the insulating member.

2. A suspension-type insulator comprising a. ilural ity of sliperposed and fle xibly con-- nected umts of WhlCh (DIIIPI'ISBS metalbers for transmitt' end members having a. laterally extending outer Henge formed thereon, the flanges of April, 1915.

the units pertainin to the insulator. efiecting, in combination, a uniform distribution 10 of the electrostatic fields surrounding the insulating members.

In testimony whereof, I have hereunto subscribed myname 'this 30th day of RAY P. JACKSON. 

